In this two year study in south central North Dakota, authors determined the responses of litter and root decomposition and nitrogen release, and soil N mineralization to grazing intensity (ungrazed, moderate, and heavy). Litter and root decomposition were consistently higher under moderate grazing than heavy or ungrazed, and occurred mostly during the growing season. The pattern of N release from litter and roots was lowest in the moderate treatment and the amount of nitrogen released from roots was 50% lower than from litter decomposition. Soil N was mineralized under moderate grazing and immobilized under heavy or no grazing, but this was not the result of a decrease in root to shoot ratio of moderate grazing, since in this study moderate grazing actually resulted in higher annual below ground net primary production. Results from this study seem to indicate that the standard grazing rule of "take half leave half" may have a significant impact in N conservation and the supply of mineral N for plant growth.
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